微波消解-石墨炉原子吸收法测定果汁中铅和镉

应用具有温度传感器附件的Ethos1型微波消解仪处理果汁样品,并采用石墨炉原子吸收法对其中铅、镉含量进行测定。对消解试剂和微波消解条件进行了筛选和优化,研究了石墨炉原子吸收的测定条件。研究表明,以HNO3-H2O2(7∶1,V/V)作为微波消解试剂,180℃,1 200W,消解8min最佳。在基体改进剂NH4H2PO4存在下,可有效地消除基体的影响,建立了微波溶样原子吸收光谱法测定果汁中Pb、Cd的方法,其Pb和Cd的检测限分别为6.0μg/L和1.0μg/L。将该法应用于果汁样品中Pb、Cd的测定,结果令人满意,RSD小于5.0%,Pb回收率为78.7%～102.4%,Cd回收率为97.8%～108.7%。通过试验,提出在微波消解前,在电热消解仪上进行预消解(140℃,20min),增大了称样量,显著降低了方法的检出限。微波消解法处理果汁样品,具有快速、简便、节约试剂、消解完全等特点,测定结果的精密度、准确度令人满意。

Microwave digestion GFA determination of Pb and Cd in fruit juice

In order to determine Pband Cd in fruit juice, fruit juice was digested and treated with microwave to detect them by GFA in this paper. We selected the best sample processing method and the excellent measurement condition. The results showed that the optimum digestion conditions are as follows： digestion conditions： HNO3 - H202 （7 ： 1,V/V）, 180 ℃, 1 200 W, 8 min. The RSD of this method is less than 5.0%. The limit of this method is： Pb 6.0/1g/L, Cd 1.0μg/L; The recovery of the method is： Pb 78.7%~102.4%, Cd 97.8%～108.7%. The de- tection limit was also decreased by increasing the sampling amount by pre-digestion at 140 ℃, 20 min. The results show that this method is simple, accurate and fast.